Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers, or as transparent sensor devices integrated with display screens to provide a touch screen interface).
Many proximity sensor devices use capacitive techniques to sense input objects. Such proximity sensor devices may typically incorporate either profile capacitive sensors or capacitive image sensors. Capacitive profile sensors alternate between multiple axes (e.g., x and y), while capacitive image sensors scan multiple transmitter rows to produce a more detailed capacitive “image” of “pixels” associated with an input object. While capacitive image sensors are advantageous in a number of respects, they do share some potential disadvantages.
Specifically, some technologies used to create capacitive images can be sensitive to errors due caused by quickly moving input objects. For example, “blurring” and/or “fragmenting” errors may be generated in systems that use advanced signal processing techniques for generating capacitive images. In both cases the errors may make it difficult to accurately determine input object position and motion. In such situations the proximity sensor device can incorrectly interpret the presence and movement of such objects. Such errors can thus result in unwanted or missed user interface actions, and thus can frustrate the user and degrade the usability of the device.
Thus, while capacitive image proximity sensor devices are advantageous in a number of respects, there is a continuing need to improve the performance of such devices. For example, to improve the responsiveness of such sensors, or to improve the sensor's resistance to errors, such as blurring and fragmenting errors.
Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.